1 /*
2 SDL - Simple DirectMedia Layer
3 Copyright (C) 1997-2006 Sam Lantinga
4
5 This library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 This library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with this library; if not, write to the Free Software
17 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18
19 Sam Lantinga
20 slouken@libsdl.org
21 */
22 #include "SDL_config.h"
23
24 /* An implementation of semaphores using mutexes and condition variables */
25
26 #include "SDL_thread.h"
27 #include "SDL_systhread_c.h"
28
29
30 struct SDL_semaphore
31 {
32 struct SignalSemaphore Sem;
33 };
34
35 #undef D
36
37 #define D(x)
38
SDL_CreateSemaphore(Uint32 initial_value)39 SDL_sem *SDL_CreateSemaphore(Uint32 initial_value)
40 {
41 SDL_sem *sem;
42
43 sem = (SDL_sem *)SDL_malloc(sizeof(*sem));
44
45 if ( ! sem ) {
46 SDL_OutOfMemory();
47 return(0);
48 }
49
50 D(bug("Creating semaphore %lx...\n",sem));
51
52 SDL_memset(sem,0,sizeof(*sem));
53
54 InitSemaphore(&sem->Sem);
55
56 return(sem);
57 }
58
SDL_DestroySemaphore(SDL_sem * sem)59 void SDL_DestroySemaphore(SDL_sem *sem)
60 {
61 D(bug("Destroying semaphore %lx...\n",sem));
62
63 if ( sem ) {
64 // Condizioni per liberare i task in attesa?
65 SDL_free(sem);
66 }
67 }
68
SDL_SemTryWait(SDL_sem * sem)69 int SDL_SemTryWait(SDL_sem *sem)
70 {
71 if ( ! sem ) {
72 SDL_SetError("Passed a NULL semaphore");
73 return -1;
74 }
75
76 D(bug("TryWait semaphore...%lx\n",sem));
77
78 ObtainSemaphore(&sem->Sem);
79 // ReleaseSemaphore(&sem->Sem);
80
81 return 1;
82 }
83
SDL_SemWaitTimeout(SDL_sem * sem,Uint32 timeout)84 int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout)
85 {
86 int retval;
87
88
89 if ( ! sem ) {
90 SDL_SetError("Passed a NULL semaphore");
91 return -1;
92 }
93
94 D(bug("WaitTimeout (%ld) semaphore...%lx\n",timeout,sem));
95
96 /* A timeout of 0 is an easy case */
97 if ( timeout == 0 ) {
98 ObtainSemaphore(&sem->Sem);
99 return 1;
100 }
101 if(!(retval=AttemptSemaphore(&sem->Sem)))
102 {
103 SDL_Delay(timeout);
104 retval=AttemptSemaphore(&sem->Sem);
105 }
106
107 if(retval==TRUE)
108 {
109 // ReleaseSemaphore(&sem->Sem);
110 retval=1;
111 }
112
113 return retval;
114 }
115
SDL_SemWait(SDL_sem * sem)116 int SDL_SemWait(SDL_sem *sem)
117 {
118 ObtainSemaphore(&sem->Sem);
119 return 0;
120 }
121
SDL_SemValue(SDL_sem * sem)122 Uint32 SDL_SemValue(SDL_sem *sem)
123 {
124 Uint32 value;
125
126 value = 0;
127 if ( sem ) {
128 #ifdef STORMC4_WOS
129 value = sem->Sem.ssppc_SS.ss_NestCount;
130 #else
131 value = sem->Sem.ss_NestCount;
132 #endif
133 }
134 return value;
135 }
136
SDL_SemPost(SDL_sem * sem)137 int SDL_SemPost(SDL_sem *sem)
138 {
139 if ( ! sem ) {
140 SDL_SetError("Passed a NULL semaphore");
141 return -1;
142 }
143 D(bug("SemPost semaphore...%lx\n",sem));
144
145 ReleaseSemaphore(&sem->Sem);
146 return 0;
147 }
148
149